Method and apparatus for neutralizing electrostatically charged fluids

ABSTRACT

A method and apparatus for neutralizing electrostatically charged flammable fluids typically occurring during handling, agitation, filtration or turbulent conditions. The method involves positioning two sets of conductive members in series with the path of fluid flow therepast and locating the sharpened edges of one set closely spaced from the rounded blunt edges of the other set and electrically isolated therefrom. The sharpedged members function to release electric charges into the fluid to neutralize it under the influence of an electrostatic field produced by an electrical potential between these sharp edges and the rounded blunt edges of the second set of conductive members. One set of conductive members is typically grounded and the other set operates at a potential closely related to the unbalanced charge present in the fluid being neutralized. The members of both sets are aligned generally with the path of flow therepast and are closely spaced from one another transversely of this path.

686,686 5/1964 Canada United States Patent [72] Inventor Frank J. Willlg 10640 Somme Way, Los Angeles, Calif. 90024 [2 1] Appl. No. 73,876

[22] Filed Sept. 21,1970

[45] Patented Dee-21,1971

[54] METHOD AND APPARATUS FOR NEUTRALIZING ELECTROSTATICALLY CHARGED FLUIDS Primary Examiner-J. D. Miller Assistant Examiner-Harry E. Moose, Jr. Attorney-Sellers and Brace ABSTRACT: A method and apparatus for neutralizing electrostatically charged flammable fluids typically occurring during handling, agitation, filtration or turbulent conditions. The method involves positioning two sets of conductive members in series with the path of fluid flow therepast and locating the sharpened edges of one set closely spaced from the rounded blunt edges of the other set and electrically isolated therefrom. The sharp-edged members function to release electric charges into the fluid to neutralize it under the influence of an electrostatic field produced by an electrical potential between these sharp edges and the rounded blunt edges of the second set of conductive members. One set of conductive members is typically grounded and the other set operates at a potential closely related to the unbalanced charge present in the fluid being neutralized. The members of both sets are aligned generally with the path of flow therepast and are closely spaced from one another transversely of this path.

METHOD AND APPARATUS FOR NEUTRALIZING ELECTROSTATICALLY CHARGED FLUIDS This invention relates to a method and apparatus for neutralizing electrostatic charges customarily created in handling certain fluids having high electrical resistivity and more particularly to a simple and highly effective method of neutralizing electrostatic charges produced in handling and filtering flammable fluids thereby to minimize the danger of explosions and fires.

It is well known that the handling of certain flammable fluids having high electrical resistivity, as for example petroleum products, can be extremely hazardous and can result in serious explosions and fires. Although all aspects of the phenomena are not thoroughly understood it is known that the transfer of these fluids through conduits and into and out of storage chambers as well as the agitation of such fluids while passing through pumps, valves and the like accessories can cause very-high electrostatic potentials of many thousands of volts. The passage of these fluids through filters is a particu larly high source of charged ions. Likewise the frictional contact of the molecules with one another and with surfaces generally is effective in producing charged ions.

It is believed that such frictional forces tend to remove electrons from normally neutral and stable molecules thereby producing free electrons. The molecule from which the electrons were detached is now unbalanced and exhibits a positive characteristic and is known as a positive ion. The free electrons tend to become attached to neutral molecules with the result that such molecules become negatively charged ions. By mechanisms not fully understood, one or the other of the negative and positive ions will be selectively neutralized by proximity to grounded elements in the flow path leaving the other type of ion in excess. It is the excess of one type of ions over the other that causes the fluid to be electrically charged and capable of building up high electrical potentials that can be dangerous. The fluid may be neutralized and made safe by the addition to the fluid of a sufficient number of ions of opposite charge.

In a number of operations typified by the usual fluid filtration system, charge separation takes place within a metal container or tank. Typically a substantially neutral fluid enters the container but withdrawn fluid carries large numbers of charged molecules. Neutralization of charge conditions occurring within the system requires a charge flow of equal size but opposite sign must be carried away or otherwise dissipated through the system wall. Typically such a charge flows into the container wall. Container walls are usually electrically connected to ground thereby providing a means for the charges to escape. If the container should be insulated from ground, it will acquire a higher and higher electrical potential until either the insulation breaks down orcharges are otherwise removed from the system by corona or sparking. The simple expedient sometimes employed of insulating the container from ground serves little or no useful function in reducing the charge content of the effluent.

Many proposals have been made heretofore dealing with the general problem outlined above but these various proposals are subject to many disadvantages are not as reliable, effective or practical as is desired. By the present invention there is provided an improved method and apparatus which has been found highly effective, efficient, thoroughly reliable. Moreover, the method is inherently self-regulating in that the greater the electrostatic charge present in the fluid, the greater its ability and effectiveness in neutralizing ions present in the fluid thereby avoiding the possibility of highly dangerous concentrations of high potential electrostatic charges.

The method utilizes at least two sets of conductive members, the members of one pair of sets being preferably closely spaced from-one another and arranged in alignment with but transversely of the flow path' of' the fluid being neutralized.

One set of conductive members is provided with pointed or sharpened edges and the adjacent edges of the other set are blunt andpreferably rounded. These sharpened and rounded edges are supported in close proximity to one another, with one set being grounded and the other being interconnected but electrically isolated from ground. In a variant embodiment a second set of conductive members is spaced upstreams of fluid undergoing neutralization and electrically connected to the blunt-edged set of members referred to above. All sets are immersed in the fluid being neutralized, those isolated from ground being capable of collecting charges from contact with the flowing fluid or from electrical connection to a separate charge collecting device within the fluid. In this manner, an electrical potential is developed on the rounded edges of the same sign as that of the net charge carried by the fluid. The electrical potential built up on the rounded edges causes a very strong electrical field to be generated in a zone embracing the sharp edges. As neutral molecules of fluid pass through this strong field some will acquire from the sharp edges a charge opposite to that of the potential on the rounded edges. These charged ions so introduced into the flowing fluid are effective to reduce its net charge. It will be recognized that the greater the net initial charge in the fluid, the greater will be the electrical potential on the body with rounded edges relative to that of the body with sharp edges and, in turn, a stronger electric field will be generated in the region of the sharp edges and more ions will be generated by this stronger field for release into the flow. In this manner and in accordance with the principles of this invention, the charged fluid is neutralized in a highly efficient and self-regulating manner. The presence of a third and smaller capacity set of conductive members spaced upstream from the sharp-edged members and electrically connected to the round-edged members enhances the effectiveness of the apparatus and method.

It is therefore a primary object of the present invention to provide a simply constructed apparatus for location in the path of moving fluid containing a net electrical charge and operating automatically and in a self-regulating manner to neutralize such charge.

Another object of the invention is the provision of two sets of conductive members respectively provided with sharpened and rounded edges in close proximity to one another and located in the path of flow of flammable fluid for the purpose of neutralizing the electrostatic charge.

Another object of the invention is the provision of high efficiency means designed for the purpose of neutralizing the electrostatic charge.

Another object of the invention is the provision of high efficiency means designed for installation in handling equipment for flammable fluid and operating automatically without need for external energy to neutralize either a net negative or positive charge present in the fluid.

Another object of the invention is the provision of means for reuniting charges present in fluid of high electrical resistivity so that effluent from a confined body of such fluid is substantially neutralized.

Another object of the invention is the provision of a novel apparatus and method of neutralizing electrostatic charges in fluids utilizing three groups of conductors in the path of fluid flowing wherein the first andthird groups are electrically connected only to one another wherein the second and third groups have sharp and rounded edges respectively closely spaced from one another in the flow path.

Another object of the invention is the provision of two sets of conductive members aligned with one another in end-toend relation and one set of which has sharpened edges spaced near and substantially equidistantly from the blunt rounded edges of the other set of conductive members and with one set connected to a source of zero potential and the other set connected together but otherwise electrically isolated.

Another object of the invention is the provision of two concentric sets of conductive members in axial alignment and distributed generally uniformly crosswise of the flow path of flammable fluid and cooperating with one another to neutralize positive and negative ions flowing therepastv Another object of the invention is the provision of a simple apparatus and method which is self-regulating and highly reliable, effective and efficient in neutralizing the charge typically developing in bodies of flammable fluids of the type having high electrical resistivity.

These and other more specific objects will appear upon reading the following specification and claims and upon considering in connection therewith the attached drawing to which they relate.

Referring now to the drawing in which a preferred embodiment of the invention is illustrated:

FIG. 1 is a transverse sectional view showing one preferred embodiment of the invention designed for installation in handling equipment for flammable fluid;

FIGS. 2 and 3 are transverse cross-sectional views on a reduced scale taken along line 22 and 3-3, respectively on FIG. I;

FIG. 4 is a fragmentary cross-sectional view through the junction of a supply conduit with a fluid storage tank and illustrating a second form of the invention neutralizing apparatus; and

FIGS. 5 and 6 are diagrammatic views of further embodiments of the invention.

Referring initially and more particularly to FIGS. 1 to 3, there is shown a first embodiment of the invention, designated generally 10, constructed for installation as a unit between two other components of handling equipment for flammable fluids such as hydrocarbons. Neutralizer 10 has a tubular main body 11 equipped with flanges 12 at its opposite ends for convenience in installing the same between similarly flanged components of equipment employed to store, handle or transport fluid to be neutralized. Usually main body 11 is formed of conductive material but it will be understood this is not essential to the practice of the principles of this invention and that nonconductive material may be employed for reasons which will become apparent below.

Rigidly supported within main body II are two sets of conductive members l5, 16. It will be understood that these members may have any shape or configuration, and comprise wires, tubes, plates, mesh, etc., and may be arranged concentrically, spirally, in tiers, etc., and may be perforate or imperforate. However, as herein shown by way of illustration, each set comprises thin smooth-surfaced tubular members 15, [6 arranged concentrically about the axis of main body 11. The individual members of each set are closely and preferably equally spaced from one another and rigidly supported by transversely extending conductive spider members l7, l8. Connector members 17 extend outwardly beyond the outermost one of members 17 and are connected by conductor 20 to a source of zero potential, such as the ground. The outer ends of members 17 are suitably secured to and supported by the wall of body member 11. If the latter is conductive it may serve as part of the conductive path 20 to ground. Otherwise, the supporting struts 17 are connected to zero potential by a conductor passing the accessory housing. Spider members 18 interconnecting conductive members 16 preferably do not project beyond the outermost one of these members and all portions of this set are electrically isolated from all other equipment by resistive spacers 22. The latter are suitably positioned to support members 16 coaxially of housing 11.

Referring more particularly to FIG. I, it will be understood that the adjacent ends of members 15 and 16 are specially contoured. Thus, edges 24 of members 15 are pointed or sharpened, whereas the adjacent ends of members 16 are relatively thick, blunt and rounded. As is well known to those skilled in this art, sharpened or pointed edges 24 are highly ineffective in retaining electrical charges whereas blunt or rounded edges 25 are highly effective in this respect.

Preferably and as herein shown, sharpened edges 24 are spaced very close to rounded edges 25, a spacing of not in excess of one-eighth inch being found highly satisfactory in neutralizing charged ions passing therebetween. Desirably, the closely spaced edges of the two sets of members are distributed throughout the cross-sectional flow path of fluid undergoing neutralization. It is also pointed out that the efficiency of this process is enhanced by exposing a substantially greater surface area of members 16 to the fluid than members 15.

Neutralizing accessory 10 is usually installed so that the flow occurs first over members 15 and then over member 16, i.e., from left to right as viewed in FIG. 1. In operation it is found that the ions flowing past the surfaces of members 16 increase the charge on these members to relatively high poten tials. This potential appears on rounded edges 25 and, being adjacent to grounded sharp edges 15, causes an electric field to be generated between these bodies. Because the latter are of small dimensions, the field strength will be concentrated in their proximity. As neutral molecules of the fluid pass through these strong fields some of them will acquire charges of a sign opposite to that of the potential on the rounded edges. These newly created ions will be swept into the flow to reduce the net charge carried therein. It will therefore be appreciated that the described apparatus and method functions in a most efficient and effective manner to neutralize a fluid carrying either a net positive or a net negative charge. This result is carried out uniformly throughout the cross section of the fluid undergoing neutralization.

A second embodiment of the invention illustrated in FIG. 4 is particularly suitable for use at the junction of a flow conduit with a large chamber such as a storage tank. The same or similar elements to those just described are designated by the same reference characters distinguished by the addition of a prime.

As there illustrated, conductive members 15, 16 are arranged at the discharge end of a flow conduit 30 entering storage tank 31. The principal structural difference between the two embodiments resides in the fact that conductive members l6 flare or radiate from their rounded ends 25' so as to project widely throughout the adjacent interior portion of storage tank 31. In order to compensate for the flaring and increasing distances between members 16', it is desirable that additional conical members 32 be inserted between adjacent ones of members 16'. Members 32 may be suitably supported and connected to members 16' by radially disposed conductive struts 34.

As will be evident from FIG. 4, the variant there illustrated so disposes charge collecting members 16', 32 as to increase their efficiency and effectiveness in contacting charged ions and collecting charges therefrom for utilization on rounded edges 25. The charges so collected are then utilized as described above to generate ions of opposite charge in the zone surrounding sharpened edges 24'.

Either of the above-described embodiments may be employed in combination with a preliminary or auxiliary charge collector to increase the effectiveness of fluid neutralization. An illustrative arrangement for this purpose is shown diagrammatically in FIG. 5 wherein the same or similar parts to those described in connection with FIGS. I to 3 are designated by the same reference character distinguished by a double prime. It will be understood that charge collectors l5" and I6" and all related structural details correspond with those described above, the significant difference being the provision of an auxiliary or primary charge collector 35, 36 of substantially smaller surface area and electrical capacity supported to non conductors 37. The auxiliary charge collector is located upstream from collectors I6" and connected to the latter by a suitable conductor 38 insulated from conduit 11' and from collectors 15". The auxiliary collector functions to collect electrostatic charges from fluid undergoing neutralization and en route to collectors 15" and 16". These charges are immediately transported to collectors 16" where they are available to aid in neutralizing the charged fluid in accordance with the principles discussed in detail above in connection with FIGS. 1 to 4.

FIG. 6 shows still another embodiment of the invention charge neutralizer installed in the fluid outlet of fluid processing equipment such as a fluid filter 40 supported on insulation mounts 41. Filter 40 has an inlet 42 and an outlet 43 each electrically isolated from adjacent portions of the flow conduits by short sections of high resistance tubing 44. As herein shown, the sets of conductive members and 16" are of similar design and construction to the corresponding conducting members described above and are supported concentrically within the outlet conduit 43 and are in intimate contact with conduits 43, 45 respectively as is indicated in FIG. 6.

In the operation of filter 40, the fluid is subjected to frictional surface contact with the filter media, not shown, but of any well-known character. The resulting surface contact and agitation produces charges of opposite polarity on the filter media and in the fluid respectively. The charge on the media passes readily to conductive members 15" either by way of housing 40 and its supporting connections with the filter media or by suitable conductors connecting the media and members 15'. It is the presence of the charges carried by the fluid which pose extreme hazards and these are neutralized as the fluid exits from the filter and flows past members 15" and 16". As the fluid flows past these two sets of members, it passes past the gap between these members and the charge present in the fluid is neutralized by the high charge of opposite polarity present on members 15". The potential difference between the two sets of members is at a maximum owing to the fact that members 16" and conduit 45 in contact therewith are grounded or otherwise held at zero potential whereas members 15 are connected to the filter media or other surface charged oppositely to the positive or negative charge prevailing in the fluid.

While the particular method and apparatus for neutralizing electrostatically charged fluids herein shown and disclosed in detail is fully capable of attaining the objects and providing the advantages hereinbefore stated, it is to be understood that it is merely illustrative of the presently preferred embodiment of the invention, and that no limitations are intended to the details of construction or design herein shown other than as defined in the appended claims.

lclaim:

1. That method of reducing hazardous conditions in a body of flammable fluid having a high electrical resistivity and likely to be excited with dangerously high electric charges due to agitation and movement past filtering equipment and past restraining walls and the like surfaces, said method comprising: passing fluid with charged ions in contact with a first set of conductive members distributed crosswise of the path of said flowing fluid and having closely spaced rounded edges along contiguous edged thereof and functioning to collect and maintain an electrical potential thereon, supporting a second set of conductive members in the path of said fluid having sharp edged closely spaced from the rounded edges of said first set of conductive members and functioning to maintain an electrical potential substantially of different polarity from that of the first set of conductive members, and utilizing the concentrated electrical field embracing said sharp edges to create ions in said fluid charged oppositely to the potential on said first set of members thereby to neutralize the fluid passing past said first and second sets of members.

2. That method defined in claim 1 characterized in the step of distributing the members of said first and second sets thereof closely to one another and aligned with but crosswise of the path of said fluid thereby to provide ample opportunity for all portions of the fluid to pass close to a surface of said first set of members and thereby to release said neutralizing charges generally uniformly into the full cross section of the fluid flow path.

3. That method of reducing hazardous conditions in a body of flammable fluid having a high electrical resistivity and likely to be excited with dangerously high electric charges due to agitation and movement past filtering equipment and past restraining walls and the like surfaces, said method comprising: collecting charges from charged ions present in said fluid on first conductive members electrically isolated from other conductive means and which conductive members are closely spaced crosswise of the path of fluid flow therepast and having at least one edge thereof rounded, supporting second conductive members spaced closely from one another crosswise of and submerged in said flowing fluid, grounding said second members and locating the sharpened edges thereof in closely spaced relation to and upstream from the rounded edges of said first conductive members, and utilizing the high potential electrical charge collecting on the rounded edges of first first conductive members to produce oppositely charged ions in fluid flowing past the sharpened edges of said second conductive members to neutralize the fluid.

4. That method defined in claim 3 characterized in the steps of utilizing conductive members having wide surface areas generally aligned with the direction of fluid flow and with said sharpened edges adjacent said rounded edges.

5. That method defined in claim 4 characterized in the step of radially offsetting said sharpened edges to lie opposite and generally between said rounded edges.

6. That method defined in claim 5 characterized in the step of arranging said first and second conductive members generally concentrically of the axis of fluid flow therepast.

7. That method defined in claim 5 characterized in the step of arranging said first conductive members in a flaring array with their rounded edges spaced relatively close together and the edges remote from said rounded edges spaced relatively widely from one another.

8. That method defined in claim 3 characterized in the step of electrically interconnecting said first conductive members to one another and said second conductive members to one another.

9. That method defined in claim 3 characterized in the step of enclosing said first and second conductive members in passage means confining the electrostatically charged fluid to a flow path passing in succession first over second members and then over said first members.

10. That method defined in claim 9 characterized in the steps of passing said charged fluid first over the conductive members having sharpened edges and then over the rounded edges of said first conductive members.

11. That method defined in claim 10 characterized in the steps of supporting said first conductive members spaced from the wall of said fluid passage means and insulated therefrom, and supporting said second conductive means from and in electrical contact with the wall of said fluid passage means.

12. Apparatus for minimizing the magnitude of the net electrostatic charge in fluid having a high electrical resistivity and often generated by turbulence and agitation occurring incident to the transfer of said fluid along a confined flow path, said apparatus comprising: first and second sets of conductive charge collecting members arranged end to end about and generally parallel to the axis of said flow path, means for supporting said first and second sets of collector members with their adjacent ends closely spaced and electrically isolated from one another, one end edge of said first set of collector members being sharpened and the adjacent end edges of said second set of collector members being blunt and rounded, and means for grounding one of said sharp-edged set of collector members and for isolating the other of said sets of collectors from ground while said apparatus is supported substantially submerged within said fluid, and said first and second sets of members cooperating with one another to neutralize electrostatic charges developed in said fluid during the transfer thereof along said flow path.

13. Apparatus as defined in claim 12 characterized in the provision of electrically conductive means interconnecting the members of each of said sets to one another.

14. Apparatus as defined in claim 13 characterized in that at least certain of the charge collecting members of one of said first and second sets flare away from one another from points adjacent the closest end of the other of said sets of charge collecting members.

15. Apparatus as defined in claim 12 characterized in the provision of conduit means surrounding each of said sets of charge collecting members with the walls thereof spaced therefrom and effective to convey said fluid past said first and second sets of members in succession.

16. Apparatus as defined in claim 12 characterized in that the surface areas of the set of members having sharpened edges is relatively small compared with the aggregate surface area of the set of members having blunt and rounded edges.

17. Apparatus as defined in claim 12 characterized in that said sharpened edged are substantially uniformly spaced between an adjacent pair of said blunt and rounded edges.

18. Apparatus as defined in claim 17 characterized in that the spacing between said sharpened and said rounded edges is of the order of /;-inch.

19. Apparatus as defined in claim 12 characterized in that the members of said first and second sets thereof are generally tubular and arranged concentrically of one another.

20. Apparatus as defined in claim 19 characterized in that said charge collecting members are smooth surfaced, thin and aligned with the flow path of said fluid.

21. That improvement in apparatus for minimizing the hazard of explosion of flammable fluid having high electrical resistivity and which hazard arises from the discharge of high electrostatic charges developing in the fluid due to agitation and movement of the fluid relative to other objects, said improvement comprising: supporting first charge collector means in the flow path of said fluid by resistive means, supporting second conductive charge collector means within the flow path of said fluid having sharp edges in closely spaced relation to blunt rounded edges of said first conductive means, and providing means for connecting said second conductive means to ground.

22. That improvement defined in claim 21 characterized in supporting a third conductive charge collector means in the flow path of said fluid and spaced upstream from said sharpedged collector means, and isolated from ground, and means electrically interconnecting said first and third charge collector means.

23. That improvement defined in claim 22 characterized in that said third charge collector means has a very substantially smaller electrical charge capacity than said first charge collector means.

24. That method defined in claim 3 characterized in the steps of supporting third conductive members spaced upstream from both said first and second conductive members and electrically connected only with said first members, and

utilizing said third conductive members to collect an electrical charge from the fluid thereby to expedite the charging of said first members with a charge having a particular polarity.

25. That method defined in claim 24 characterized in the step of utilizing third charge collector members having an electrical capacity substantially less than the electrical capacity of said first collector members.

26. That method defined in claim 1 characterized in the step of connecting said sharp-edged set of conductive members to a source of zero potential, and electrically isolating said set of round-edged conductive members from conductive means external to the fluid undergoing neutralization.

27. That method defined in claim 1 characterized in the steps of connecting said round-edged set of conductive members to a source of zero potential, and electrically connecting said set of sharpedged conductive members to means in contact with flowing and agitated fluid undergoing neutralization.

28. That method defined in claim 27 characterized in the step of locating said first and second sets of conductive members in the path of fluid discharging from fluid processing means.

29. That method defined in claim 27 characterized in the step of utilizing the flow of charged fluid past said set of electrically isolated conductive members.

30. That improvement in apparatus for minimizing the hazard of explosion of flammable fluid havin high electrical resistivity and which hazard arises from the ischarge of high electrostatic charges developing in the fluid due to agitation and movement of the fluid relative to other objects, said improvement comprising: supporting first sharp-edged conductive means in the flow path of fluid to be neutralized, supporting second conductive means having blunt rounded edges in said fluid with said rounded edges closely spaced from said sharp edges, connecting one of said first and second conductive means to a source of zero potential, and connecting the other thereof to means in contact with portions of said fluid subject to agitation and friction while flowing over other objects.

31. That improvement defined in claim 30 characterized in the step of connecting said sharp-edged conductive means to the means in contact with flowing and agitated fluid, and connecting said round-edged conductive means to a source of zero potential.

32. That improvement defined in claim 30 characterized in the step of connecting said sharp-edged conductive means to a source of zero potential and said round-edged conductive means to said means in contact with flowing and agitated fluid. 

2. That method defined in claim 1 characterized in the step of distributing the members of said first and second sets thereof closely to one another and aligned with but crosswise of the path of said fluid thereby to provide ample opportunity for all portions of the fluid to pass close to a surface of said first set of members and thereby to release said neutralizing charges generally uniformly into the full cross section of the fluid flow path.
 3. That method of reducing hazardous conditions in a body of flammable fluid having a high electrical resistivity and likely to be excited with dangerously high electric charges due to agitation and movement past filtering equipment and past restraining walls and the like surfaces, said method comprising: collecting charges from charged ions present in said fluid on first conductive members electrically isolated from other conductive means and which conductive members are closely spaced crosswise of the path of fluid flow therepast and having at least one edge thereof rounded, supporting second conductive members spaced closely from one another crosswise of and submerged in said flowing fluid, grounding said second members and locating the sharpened edges thereof in closely spaced relation to and upstream from the rounded edges of said first conductive members, and utilizing the high potential electrical charge collecting on the rounded edges of first first conductive members to produce oppositely charged ions in fluid flowing past the sharpened edges of said second conductive members to neutralize the fluid.
 4. That method defined in claim 3 characterized in the steps of utilizing conductive members having wide surface areas generally aligned with the direction of fluid flow and with said sharpened edges adjacent said rounded edges.
 5. That method defined in claim 4 characterized in the step of radially offsetting said sharpened edges to lie opposite and generally between said rounded edges.
 6. That method defined in claim 5 characterized in the step of arranging said first and second conductive members generally concentrically of the axis of fluid flow therepast.
 7. That method defined in claim 5 characterized in the step of arranging said first conductive members in a flaring array with their rounded edges spaced relatively cLose together and the edges remote from said rounded edges spaced relatively widely from one another.
 8. That method defined in claim 3 characterized in the step of electrically interconnecting said first conductive members to one another and said second conductive members to one another.
 9. That method defined in claim 3 characterized in the step of enclosing said first and second conductive members in passage means confining the electrostatically charged fluid to a flow path passing in succession first over second members and then over said first members.
 10. That method defined in claim 9 characterized in the steps of passing said charged fluid first over the conductive members having sharpened edges and then over the rounded edges of said first conductive members.
 11. That method defined in claim 10 characterized in the steps of supporting said first conductive members spaced from the wall of said fluid passage means and insulated therefrom, and supporting said second conductive means from and in electrical contact with the wall of said fluid passage means.
 12. Apparatus for minimizing the magnitude of the net electrostatic charge in fluid having a high electrical resistivity and often generated by turbulence and agitation occurring incident to the transfer of said fluid along a confined flow path, said apparatus comprising: first and second sets of conductive charge collecting members arranged end to end about and generally parallel to the axis of said flow path, means for supporting said first and second sets of collector members with their adjacent ends closely spaced and electrically isolated from one another, one end edge of said first set of collector members being sharpened and the adjacent end edges of said second set of collector members being blunt and rounded, and means for grounding one of said sharp-edged set of collector members and for isolating the other of said sets of collectors from ground while said apparatus is supported substantially submerged within said fluid, and said first and second sets of members cooperating with one another to neutralize electrostatic charges developed in said fluid during the transfer thereof along said flow path.
 13. Apparatus as defined in claim 12 characterized in the provision of electrically conductive means interconnecting the members of each of said sets to one another.
 14. Apparatus as defined in claim 13 characterized in that at least certain of the charge collecting members of one of said first and second sets flare away from one another from points adjacent the closest end of the other of said sets of charge collecting members.
 15. Apparatus as defined in claim 12 characterized in the provision of conduit means surrounding each of said sets of charge collecting members with the walls thereof spaced therefrom and effective to convey said fluid past said first and second sets of members in succession.
 16. Apparatus as defined in claim 12 characterized in that the surface areas of the set of members having sharpened edges is relatively small compared with the aggregate surface area of the set of members having blunt and rounded edges.
 17. Apparatus as defined in claim 12 characterized in that said sharpened edged are substantially uniformly spaced between an adjacent pair of said blunt and rounded edges.
 18. Apparatus as defined in claim 17 characterized in that the spacing between said sharpened and said rounded edges is of the order of 1/8 -inch.
 19. Apparatus as defined in claim 12 characterized in that the members of said first and second sets thereof are generally tubular and arranged concentrically of one another.
 20. Apparatus as defined in claim 19 characterized in that said charge collecting members are smooth surfaced, thin and aligned with the flow path of said fluid.
 21. That improvement in apparatus for minimizing the hazard of explosion of flammable fluid having high electrical resistivity and which hazard arises from the discharge of high electrostatic chargEs developing in the fluid due to agitation and movement of the fluid relative to other objects, said improvement comprising: supporting first charge collector means in the flow path of said fluid by resistive means, supporting second conductive charge collector means within the flow path of said fluid having sharp edges in closely spaced relation to blunt rounded edges of said first conductive means, and providing means for connecting said second conductive means to ground.
 22. That improvement defined in claim 21 characterized in supporting a third conductive charge collector means in the flow path of said fluid and spaced upstream from said sharp-edged collector means, and isolated from ground, and means electrically interconnecting said first and third charge collector means.
 23. That improvement defined in claim 22 characterized in that said third charge collector means has a very substantially smaller electrical charge capacity than said first charge collector means.
 24. That method defined in claim 3 characterized in the steps of supporting third conductive members spaced upstream from both said first and second conductive members and electrically connected only with said first members, and utilizing said third conductive members to collect an electrical charge from the fluid thereby to expedite the charging of said first members with a charge having a particular polarity.
 25. That method defined in claim 24 characterized in the step of utilizing third charge collector members having an electrical capacity substantially less than the electrical capacity of said first collector members.
 26. That method defined in claim 1 characterized in the step of connecting said sharp-edged set of conductive members to a source of zero potential, and electrically isolating said set of round-edged conductive members from conductive means external to the fluid undergoing neutralization.
 27. That method defined in claim 1 characterized in the steps of connecting said round-edged set of conductive members to a source of zero potential, and electrically connecting said set of sharp-edged conductive members to means in contact with flowing and agitated fluid undergoing neutralization.
 28. That method defined in claim 27 characterized in the step of locating said first and second sets of conductive members in the path of fluid discharging from fluid processing means.
 29. That method defined in claim 27 characterized in the step of utilizing the flow of charged fluid past said set of electrically isolated conductive members.
 30. That improvement in apparatus for minimizing the hazard of explosion of flammable fluid having high electrical resistivity and which hazard arises from the discharge of high electrostatic charges developing in the fluid due to agitation and movement of the fluid relative to other objects, said improvement comprising: supporting first sharp-edged conductive means in the flow path of fluid to be neutralized, supporting second conductive means having blunt rounded edges in said fluid with said rounded edges closely spaced from said sharp edges, connecting one of said first and second conductive means to a source of zero potential, and connecting the other thereof to means in contact with portions of said fluid subject to agitation and friction while flowing over other objects.
 31. That improvement defined in claim 30 characterized in the step of connecting said sharp-edged conductive means to the means in contact with flowing and agitated fluid, and connecting said round-edged conductive means to a source of zero potential.
 32. That improvement defined in claim 30 characterized in the step of connecting said sharp-edged conductive means to a source of zero potential and said round-edged conductive means to said means in contact with flowing and agitated fluid. 